The Rocky Mountain West — reliably Republican in presidential politics during the Reagan era — is now a battleground.

And we love it.

When we voted knee-jerk Republican, the GOP took us for granted and Democrats wrote us off. Now empowered as swing voters, we can demand attention from the federal government for our special needs.

Like all Americans, Westerners grumble at the rising cost of gasoline and home heating. But we also host the nation’s greatest storehouse of natural resources and worry about how the rush to drill for gas and oil, mine uranium and eventually perhaps produce oil shale can affect our fragile environment and precious water resources. And we can’t wait for both parties to address those issues.

Two new-breed Western Democrats, Colorado Sen. Ken Salazar and Arizona Gov. Janet Napolitano, pressed the theme of the West as a swing region Monday as the Democratic convention opened in Denver. Napolitano noted just six years ago that Republicans held the governorships of all eight Rocky Mountain states. Today, Democratic governors sit in five of the statehouses: Arizona, New Mexico, Montana, Wyoming and Colorado. Democrats believe they have a fighting chance of carrying four of those states — all but Wyoming — plus Nevada for Barack Obama.

Collectively, the eight Rocky Mountain states — all of which went for George W. Bush in 2004 — control 44 electoral votes. Capturing just the three where Democrats think their chances are brightest, New Mexico, Colorado and Nevada, would put 19 electoral votes to Obama. That’s almost as many as the 20 votes from the traditional swing state of Ohio and enough to have made John Kerry president if he had carried them in 2004. Add Arizona’s 10 electoral votes and Montana’s three and Obama could conceivably harvest 42 electoral votes in the Rockies.

In the end, we don’t really expect McCain to lose his home state. But he can’t take it for granted, either. As Napolitano noted, swift growth means that “One in four Arizonans has never voted in an election with McCain on the ballot” since his last Senate race in 2004.

An extensive analysis by Andrew Myers of the demographic and political changes now driving the West is available at WesternMajorityProject.org.

The key point politically is that even if McCain sweeps all eight Rocky Mountain states, he will have to put major resources into a region the GOP once took for granted. In a fall campaign where McCain, relying on public financing, is likely to be heavily outspent by Obama, money spent in the West can’t be used in Florida, Ohio or other battlegrounds.

It also means that no matter who wins the White House, the West will no longer be ignored.